We have recently developed methods for isolating substantial numbers of idiotype-specific suppressor T cells. During the coming year we will investigate factors that lead to the production of such large numbers of specific T cells (up to 8-10% of the entire T cell population). We will also attempt to isolate specific suppressive factors from the membranes or cytoplasm of such cells and to begin their characterization. Other studies will be concerned with the development of improved methods for generating large quantities of ascitic fluids in mice and guinea pigs. Such fluids have already proved to be highly useful as a source of large amounts of specific antibodies and for generating lymphocytes that can be used in immunological studies without sacrificing the donor animal. A third line of investigation relates to amino acid sequences of molecules bearing a cross-reactive idiotype associated with the anti-p-azophenylarsonate antibodies of A/J mice. In collaboration with Dr. J.D. Capra, the complete sequence of the Vl region has already been obtained, as well as partial sequences on the VH region. We are generating large amounts of antibody which we will isolate and purify on the basis of idiotypic specificity, in order to permit completion of the sequencing work on the variable region of the heavy chain.